What are the causes of intracranial hemorrhage (ICH) in a young person?

Causes of Brain Bleed in Young People

Vascular malformations are the leading cause of intracranial hemorrhage in young people, accounting for approximately 40-50% of cases, with arteriovenous malformations (AVMs) being the most common specific etiology. 1

Primary Causes by Frequency

Vascular Malformations (40-50% of cases)

• AVMs and arteriovenous fistulas represent 32-49% of pediatric and young adult intracranial hemorrhages 1, 2, 3
• Cavernous malformations are the second most common vascular anomaly causing hemorrhage 1
• Intracranial aneurysms account for approximately 34% of spontaneous hemorrhages in young patients, though they are relatively uncommon in children (<2% of all aneurysm cases) 1, 2
• Aneurysms in young people more commonly involve the posterior circulation and are more likely to be giant aneurysms compared to adults 1

Hematologic and Coagulation Disorders (25-30% of cases)

• Thrombocytopenia causes 11.8% of pediatric hemorrhages, with risk becoming significant when platelet counts drop below 20,000/mm³ 1
• Coagulation factor deficiencies account for 14.7% of cases, including hemophilia (Factor VIII deficiency), Factor XIII deficiency, and vitamin K deficiency 1
• Severe factor deficiencies (≤5% of normal activity) cause spontaneous hemorrhage, while milder deficiencies typically require trauma as a trigger 1
• Sickle cell disease can cause hemorrhagic infarction, particularly in younger children 1

Brain Tumors (13% of cases)

• Approximately 13.2% of pediatric intraparenchymal hemorrhages occur into highly malignant brain tumors 1
• These cases initially present as apparent primary hemorrhages before tumor diagnosis is established on complete imaging 1

Cerebral Venous Sinus Thrombosis (5% of cases)

• CVST can cause both intracerebral hemorrhage and subarachnoid hemorrhage 1
• Best diagnosed with MR venography, though sometimes identifiable on standard MRI 1

Other Causes

• Sympathomimetic drug use accounts for approximately 4% of cases in young adults 3
• Hypertension is uncommon in children but becomes more relevant in patients >31 years old, causing primarily basal ganglia hemorrhages 1, 3
• Infectious (mycotic) aneurysms develop distally in the cerebral vasculature and are often multiple, causing ICH and subarachnoid hemorrhage 1

Age-Specific Patterns

Neonates and Infants

• Maternal medication exposure (warfarin, phenytoin, barbiturates) causes vitamin K-dependent coagulation factor deficiency 1
• AVMs in neonates present with high-output cardiac failure and have worse outcomes than older presentations 1
• Vein of Galen malformations cause hydrocephalus from aqueductal compression 1

Children and Adolescents

• AVMs are most common in patients <20 years old (odds ratio 2.80) 3
• Aneurysm presentation is biphasic: most common before age 2 or after age 10 1

Young Adults (20-40 years)

• Hypertension becomes more relevant as a cause in patients >31 years (odds ratio 3.48) 3
• Lobar location predominates (55% of cases) 3

Critical Diagnostic Approach

A complete evaluation identifies a cause in approximately 90% of cases when standard cerebral angiography is performed. 1

Essential Workup Components

• CT without contrast is the initial diagnostic standard 4
• Cerebral angiography should be performed when noninvasive tests fail to establish an origin, as it identifies causes missed by other modalities 1
• MRI with gradient-echo sequences is superior for detecting chronic hemorrhages and microbleeds 4
• MR venography to exclude cerebral venous sinus thrombosis 1
• Complete hematologic evaluation including platelet count, coagulation studies, and factor levels 1

Important Clinical Distinctions

Hypertension is NOT a common cause in children

Unlike adults, long-standing arterial hypertension rarely causes brain hemorrhage in the pediatric population 1

Location provides diagnostic clues

• Lobar hemorrhages suggest vascular malformations, cavernous angiomas, or (in older adults) cerebral amyloid angiopathy 4, 3
• Basal ganglia hemorrhages in young people suggest hypertension when present 3
• Multiple hemorrhages suggest infectious aneurysms, coagulopathy, or venous thrombosis 1

Trauma history is critical

With severe coagulation deficiencies, 6 of 7 patients with ICH had trauma history, whereas spontaneous hemorrhage occurs primarily with severe deficiency 1

Common Pitfalls to Avoid

• Assuming hypertension is the cause without thorough vascular imaging—this leads to missed treatable vascular malformations 1
• Stopping evaluation after initial CT—angiography identifies causes in nearly all cases when performed 1
• Overlooking underlying tumors—13% of pediatric hemorrhages are into malignant tumors 1
• Missing associated conditions like coarctation of the aorta, polycystic kidney disease, or Ehlers-Danlos syndrome that predispose to aneurysms 1